


Radius of Convergence

by oppisum



Series: Polyamory & Pizza ‘verse [1]
Category: Supernatural
Genre: Age Difference, Alternate Universe - Human, Coming Out, Lap Sex, M/M, Pining Sam, Polyamory, Professor Castiel, Queer Themes, Relationship Negotiation, established Destiel, first time ot3
Language: English
Status: Completed
Published: 2014-05-11
Updated: 2014-05-11
Packaged: 2018-01-24 07:43:55
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 11,399
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/1597055
Author URL: https://archiveofourown.org/users/oppisum/pseuds/oppisum
Summary: <blockquote class="userstuff">
              <p>Maybe some faulty part of Sam’s brain had crossed up the various definitions of love when it came to Dean, but he couldn’t bring himself to regret it. Filial love, friendly love, and romantic love had all been melted down and poured into the mold of Love for Dean.</p><p>Cas’ smile was soft and kind and made Sam think he understood a little too well why Sam was sitting on the back steps staring up at the stars.</p><p>
  <i>Or, in which Cas really just wants the Winchesters to quit angsting and embrace polyamory.</i>
</p>
            </blockquote>





	Radius of Convergence

**Author's Note:**

> 'Verse Soundtrack: [HERE](http://8tracks.com/oppisum/sins-of-my-youth-polyamory-pizza)
> 
> Thanks to [meatball42](http://archiveofourown.org/users/Meatball42/pseuds/Meatball42) for betaing and [csanduhs](http://csanduhs.tumblr.com/) for audiencing.

“Dean, have you seen my Sociology book? I know-”

Sam broke off as he rounded the open door of the master bedroom. Dean was on the bed, naked and moving with an equally bare Castiel bodily wrapped around him.

Castiel, as in Dean’s best friend and Sam’s former professor _Castiel Novak._

Sam’s breath caught.

He’d walked in on Dean plenty of times over the twenty years they’d lived together, but it had never been like this. For all that sex was supposedly intimate and close, Dean always kept some semblance of distance between him and his partners. Oh, they were perfectly happy and fulfilled from what Sam had seen, but he knew, in that way he knew all the things his brother never said, that Dean kept his distance intentionally.

Now, though, there wasn’t a millimeter between them. Dean was leaned back on his haunches, Cas straddling his lap. Cas had one muscular leg hitched up around Dean’s hip and both hands fisted on his back. One of Dean’s arms was linked around the smaller man’s shoulder, holding them chest to chest, while his other hand petted Cas’ flank in time with their movement. The pair worked up and down in unbroken synchronicity, breaths stuttering out noisily in the otherwise still room.

Sam watched, transfixed.

Neither of them had even noticed him.

Just as that thought crossed his mind, Cas turned his face from where it was buried against Dean’s neck and held Sam’s gaze. His blue eyes were sharp but not angry, and he smiled softly. The smile wasn’t lascivious or taunting or a “haha, I just caught you ogling your brother during sex” smile. It was soft and kind and maybe a little too understanding.

Sam stepped back instinctively, fully intending to make a run for it, but the scene before him shifted. Cas’ mouth fell open and his eyes went hooded. The low breathy sounds he was making increased in volume and pitch. Dean’s rhythm stuttered, and his head fell back, eyes closed in pleasure. He shuddered, still clinging to Cas.

After a moment, both of them stilled completely. The leg wrapped around Dean relaxed out, and Cas’ fists unclenched to smooth down the other man’s back. To Sam’s surprise, even as they came down off their high, they didn’t pull apart.

Dean shifted Cas up just enough to pull out of him, and heat burned low and sparking in Sam’s stomach as he realized his brother wasn’t wearing a condom. Without opening his eyes, Dean flopped them gracelessly back onto the pillows and arranged Cas against his chest.

The reality of watching his brother and former professor have sex – _hot, bendy, intimate sex_ – finally clicked into place, and Sam blindly took a step back, smacking his head into the side of the doorframe with a loud crack. Dean’s eyes flew open as Sam raised a hand to the back of his head.

“Sam! Wha-?”

He realized what he must look like hovering in the doorway, pupils dilated and an obvious bulge in his jeans.

Sam didn’t wait to see his brother’s reaction. He turned and all but ran to the small bathroom of the rental house they shared. The lock didn’t work, but that hardly seemed to matter. He turned the tap all the way to cold and splashed the icy water over his face several times. He paused, elbows braced on the counter, and stared down at the water cupped in his shaky palms then looked up at the mirror. The face reflected there looked unfamiliar, bangs soaked and eyes wide.

Cas and Dean had been best friends since shortly after the Winchesters moved to Palo Alto. They’d met when Cas brought his car into Dean’s shop for engine trouble, and the brothers had spent a month blissfully unaware that Dean’s “Cas” and Sam’s “Professor Novak” were one in the same. That is, until Sam had come home one afternoon to find his freshman philosophy professor sitting on their couch.

But the awkwardness had faded quickly as Cas became a regular fixture in the Winchesters’ lives. By the time spring semester rolled around, there was nothing unusual about having Cas– thankfully no longer Professor Novak to Sam – over for pizza and a beer every Friday night. Sure, Sam still saw him around campus and even ate lunch in his office once in a while, but it was as a friend, not as a student.

Sam pressed his forehead to the faux marble counter.

He’d known for several months that Cas and his brother were more than friends, but he’d never been sure how to bring up the subject. Dean had been discreet. Weirdly so. Sam guessed it was because Cas was a Stanford professor. Maybe not his professor anymore, but an undergraduate professor, nonetheless.

Cas really should tell Dean that a little fraternization always went unnoticed in an institution the size of Stanford as long as lawsuits and blatant favoritism weren’t involved. As a sophomore on the pre-law track, Sam would never need to take another of _Professor Novak’s_ classes, so theoretically, everything was nice and ethical.

Sam settled on the side of the tub, elbows on his knees and face in his hands.

Seeing Dean and Cas together wasn’t what bothered him. He was happy for them. They were both good men who deserved to be happy. No, what bothered him was that he’d stood there and watched. He’d watched the play of muscle over Dean’s back, watched the way the light caught the sweat of his brother’s neck. Sam had watched the way his brother’s body twined around Cas’ leanly muscled frame.

A shuttering breath escaped his lips, and Sam dug the heel of his hand against his eyes, desperate to get the image out of his head.

He’d known since puberty that there was something “not right” about him. Normal people didn’t lust after their brother, didn’t see their brother’s face when they jerked off. Sam knew “Dean” shouldn’t be the first name that came to mind when asked if he’d ever been in love.

Sam knew this, and he’d come to terms with it long ago. He’d had to if he didn’t want to drive himself crazy. So he was a little fucked in the head. It wasn’t a big deal unless he made it one. Sure, guilt occasionally ached in his stomach, but he did his best to ignore it and move on with his life. He dated girls and fought over the last brownie with Dean. Sam could never resent Cas. Hell, he wasn’t even jealous of Cas. He was just… confused, more than anything.

“Your head okay?”

Sam’s gaze snapped up. His brother stood in the doorway, arms crossed over his chest. He wore boxers and a backwards t-shirt, hair sticking out at odd angles.

“I- Yeah, yeah. Fine. Thanks for checking,” Sam said.

He hoped that was the end of the discussion. They could close the topic, bury it, and pretend it never happened in true Winchester form.  Apparently, though, Cas’ earnest insistence that “feelings matter” had made an impression on Dean, who lowered himself gingerly to the side of the tub.

“That was one hell of a way for you to find out about Cas and I.”

Sam huffed out a laugh. “I already knew, Dean. Neither of you are exactly subtle.”

“Oh, well…” Dean ran his hands through his hair. “Look, Sammy, I know he’s… Jesus, I know he was your professor last year, but-”

“Dean,” Sam cut in. “It’s fine.”

“Really, because you don’t look like it’s fine.”

“It’s not that, I promise.”

“Is it the age thing? I mean, he’s older than me, but I honestly didn’t think that would be the problem.”

“He’s thirty-three, not sixty. There’s only a nine year gap between you. Besides,” Sam faltered, unsure how to phrase what he wanted to say. Their respective sexualities weren’t something they’d ever discussed outright. Hell, Sam didn’t even think Dean knew he was into guys, too. “Most gay men start out dating guys older than them.”

Dean looked down at the linoleum. “I know it’s weird. There’s a lot of stuff we never talked about. I mean, me, with dudes. I just-- I want to make sure you’re okay with this.”

“With you dating Cas or with you dating guys?”

“Either. Both,” Dean said. His voice came out rough and dry.

Sam softened, temporarily setting his own fears aside. Clearly this was something Dean had been worrying about. Sam had assumed Dean was keeping their relationship secret for fear it would affect Cas’ career or Sam’s academics. After all, who knew what the fallout would be if it got out that Cas was sleeping with a former student’s brother, but maybe that wasn’t the reason.

“Dude, I’ve known you were into guys since we were teenagers. You know that. Remember that time I walked in on you and some guy from Lawrence?”

“But that’s the difference, isn’t it? He was just ‘some guy.’ Fucking a dude is one thing. Da-” Dean choked, cleared his throat, and tried again. “Dating a guy, dating one of our mutual friends –that’s different.”

Sam wanted to laugh. Not at Dean, per say, but at the dark humor of the situation. Here his brother was worrying about being gay while Sam had skipped right over the gay freak out and gone straight for the incest freak out.

“Cas is a great guy. You both deserve this. Besides, he’s older than you, yeah, but he’s got his shit together. Maybe that’s what you need right now. After Dad-- after everything we’ve been though, maybe you deserve not to be the responsible one sometimes.”

And Sam meant it. He could never begrudge the two of them what they had. Sure, he wanted Dean, but not at the expense of his brother’s happiness. Seeing the worry line disappear from between his brother’s brow and having Dean happy and smiling meant more to Sam than _having_ Dean ever would.

Dean grew up so fast after their dad died. Sam had been sixteen, and Dean refused to let child services take him, instead opting to become his brother’s guardian. Nothing changed between them, really. John may have been the bread-winner, but it was Dean who really raised Sam. Things had been tough without the money John made as a bounty hunter, but Dean worked. He worked and made sure his little brother could go to college.

For that Sam loved his brother, loved him more than he’d ever know how to express with words. Maybe some faulty part of Sam’s brain had crossed up the various definitions of love when it came to Dean, but he couldn’t bring himself to regret it. Filial love, friendly love, and romantic love had all been melted down and poured into the mold of Love for Dean. Dean would never know, and Sam was okay with that. It was one less thing his brother needed to worry about.

 “And Dean? The whole,” Sam waved his hand vaguely, “Cas-being-a-dude thing doesn’t bother me. You’re my big brother. That’s not going to change because of who you date. Men, women, flying purple people eater furries; it doesn’t make a difference to me.”

“Thanks, Sam,” Dean said.

“I mean, it’s not just- You’re not the only one who-” Sam broke off and let out a frustrated sign. “I like men, too, okay?”

“Oh, um, I kinda’ wondered, but,” Dean shrugged and let the unfinished sentence hang. “You know it’s okay, right? I mean Jesus, Sammy, it sure as shit won’t bother me if you’re gay or whatever.”

A genuine smile took over Sam’s lips. “I know. That’s why I never brought it up. And I’m bisexual, by the way. Leaning towards guys.”

“Yeah, okay. Thanks for telling me. I really do appreciate it.” Dean laughed dryly. “Fuck, what would Dad say if he was alive to hear this.”

“It doesn’t matter what Dad would say.”

“I know,” Dean said. “I made my peace with that a long time ago.”

Dean quirked a smile and stretched his legs out in front of him, gripping the side of the tub for balance. “Besides, I don’t think he’d of disowned us. He’d probably just be really fucking confused. Both of his sons prefer dick but are also cool with pussy.”

Sam pulled a face. “Nice, Dean. Very eloquent.”

Dean stayed silent for a beat.

“How long were you standing there?” He asked, and then held up a hand. “Wait-- Don’t answer that. Just, look. It’s okay. Curiosity, right?”

“Right.” Sam forced a smile. At twenty years old, “curiosity” meant watching gay porn on dubious websites, not perving on your older brother in bed with your former professor.

Dean smirked. “Besides, Cas is hot.”

Sam barked out a laugh. “Yeah, he is.”

No way was he going to disagree. Dean may have been Sam’s main focus, but that wasn’t to say he hadn’t taken the chance to ogle Castiel, too. Sam knew more than one girl minoring in philosophy solely because of Cas in a waistcoat.

And his eyes.

And possibly his hair.

So maybe Sam had a bit of a crush on “Professor Novak” during his philosophy class. Who wouldn’t when the professor was gorgeous _and_ kind? It’d never really mattered, though. Even after the giant ‘Off Limits’ sign of Cas being his professor had been taken down, Sam had seen the way his brother looked at the older man, and no way was he going to stand in the way.

“Okay, well, I’m gonna’ take a bath,” Dean said, derailing Sam’s train of thought. He blinked at Sam with faux earnestness. “That is, if you’re done being emo in the bathroom.”

“Jerk.”

“Bitch. Now get your ass out so I can shower in peace.”

As the door clicked shut behind him, Sam decided against going to his room to study. His Sociology midterm wasn’t until next week, and there was no way he’d absorb anything he read right now even if he could find his book. Instead, he pulled open the back door and sat on the cold concrete steps. The house they lived in was far enough out of Palo Alto that rent was cheap and the stars were visible through the light pollution.

Sam craned his neck to look up at them.

“Home” had never been a place for Sam. Home was the growl of the impala and the spray of stars on a clear night. It was Dean’s arm wrapped around his shoulder and a cold beer shared between them. And, more recently, home was the soft rumble of Castiel’s laugh and a rumpled overcoat on the back of a kitchen chair.

Sam wanted to bottle what they had– his brother, Cas, the laughter, the Friday night pizza – and keep it forever, but he didn’t know how. It couldn’t last forever, he knew. One day he’d be expected to go his own way, move out, and have a career. Cas would be by Dean’s side and in his bed long after Sam stopped being a fixture in their day to day lives, and the prospect of only seeing them on special occasions made his chest ache.

Even now, he was terrified of screwing up what they had. Tonight had been a terrible mistake. If Dean hadn’t been so caught up in his own fears, well, Sam didn’t want to think about it. Dean was smarter than he gave himself credit for and perceptive enough to see everything Sam had spent years hiding if he looked.

 “Knock, knock.”

Sam startled and looked back over his shoulder.  Cas leaned against the backdoor, bare feet crossed at the ankles. He was clean and put-together in a waistcoat, jeans, and lavender button-down. All the trappings of “Professor Novak” were there, only now instead of artfully gelled sex hair, he had _actual_ sex hair.

“Mind if I join you?”

Without waiting for a response, the older man settled next to Sam on the narrow steps, close enough for their knees to touch.

Castiel sat as if in prayer, hands clasped and head bowed. The dim glow from the house smoothed his laugh lines and made him look younger than he ever did under a lecture hall’s florescent lights. The night was still apart from the faint breeze ruffling their hair, and Sam found himself unwilling to break the silence, instead content to study the play of shadows around the older man’s downcast eyes.

He could hardly believe this was the same man he’d just seen his brother vigorously fucking.

Cas glanced sideways at him, catching him staring for the second time that night.

“It’s okay, you know,” he said.

“I know. You two are good together; I’m happy for you."

Sam felt like he was saying that a lot tonight.

“That’s not what I meant,” Cas said.

Sam tried to keep his smile polite. “I’m not having a crisis of sexuality, if that’s what you’re worried about.”

“I wasn’t referring to your interest in men, either, Sam.”

The knowing, sad smile Cas had given him earlier echoed through Sam’s mind, and his stomach knotted with shame. He tried to keep his voice under control. “Then I don’t know what you’re talking about.”

“Yes, you do.”

And what exactly was the appropriate response to that? Sam looked down, unable to hold his gaze.

“It’s okay,” Cas repeated.

 “No, it really isn’t.”

Cas put a hand on his shoulder. “Sam, look at me. Please.”

Maybe it was the bare feet, but he knew he wasn’t talking to the professor right now. This was Cas, the dorky guy who secretly loved Jason Statham movies despite having a Ph.D. and who, if Sam was honest, had become one of his closest friends and confidants. Somewhere between eating lunch in Cas’ office after a rough day and fighting with him over pizza toppings, it had become apparent that Cas wasn’t just Dean’s friend; he was Sam’s friend, too.

Sam up looked at him, then. His expression was intent but not upset or repulsed, and the relief of that made Sam’s chest loosen.

“You’re not the first or the last person who’s felt like this,” Cas said, gripping his shoulder steadily. “I know you probably read all the psychology books on it, but I’m going to tell you something none of them ever will: It’s okay. There’s nothing wrong with you, Sam. You’re not broken or twisted or whatever else you’ve told yourself.”

The words felt like a benediction, as if Sam was being pardoned for a sin he’d never meant to commit. Something in them assuaged the guilt he’d carried for so long, and years spent terrified of discovery felt lifted from his shoulders. His worst fear had been realized, and yet here Cas was telling him that it was okay.

He’d spent so many years ignoring the surge of want and shame that spiked through him whenever he saw his brother shirtless.This was the acceptance Sam never believed he could have. This wasn’t someone blaming him or labeling him broken. This was Cas still looking at him with kind, understanding eyes.

Sam didn’t notice the tears until Cas lightly brushed them from his cheeks. He pulled Sam down to his shoulder, and Sam’s arms instinctively wrapped around his narrow waist.

Cas smelled like sex and Dean and hazelnut.

“How long?” he asked.

“Since I was thirteen.” Sam’s voice came out muffled against Cas’ collar.

“Jesus,” Cas breathed, bringing a hand up to pet through Sam’s hair. “And you never told anyone?”

“This is--” Sam’s voice broke. He cleared his throat and tried again. “This is incest we’re talking about. Not exactly something you can just slip into conversation. Why are you even condoning this?”

“Because you deserve not to feel like a pariah because of an attraction you can’t help that doesn’t hurts anyone. There’s no coercion or abuse of power in this situation. You’re both consenting adults capable of making your own choices.”

Silence fell again, and Cas tightened his hold on Sam. He tilted his head back to look at the night sky, his stubble prickling the side of the taller man’s face. Finally, he took a breath.

 “You’re so young. You take so much on yourself that sometimes I forget that.” Cas sighed. “There are worse transgressions than loving your brother.  At least in my experience, consensual incest is hardly the worst sin.”

Part of Sam really wanted to ask what, exactly, his experience was. The rumors circulating campus about Professor Novak’s younger years were nothing if not varied. Drugs, alcohol, orgies – you name it, rumor had it Castiel Novak tried it as an undergrad finally free from his conservative family.

Sam had learned to take the rumors with a grain of salt. Sure, Cas was more laid-back than the average Stanford professor and really enjoyed swearing during lectures, but otherwise Sam had never seen much of the weed-and-orgies Castiel in the well dressed Professor Novak.

“You should tell him,” Cas said seriously.

Sam pulled back and gave Cas his best ‘are you insane?’ expression. “No. No way. He’d never look at me the same again. Christ, I’d be lucky if he’d even look at me at all.”

“I don’t think Dean would react as poorly as you think.”

 “Maybe it’s not a big deal to you, but this isn’t something you can just say to your brother. If I tell him, what’s he supposed to think, huh? Knowing him, he’d find a way to blame himself, and like hell am I putting that on him. He’s got enough to worry about without finding out his little brother is fucked in the head.”

“Sam, you misunderstand me. I don’t believe you’re the only one feeling like this.”

“You can’t seriously be suggesting that Dean-- that he-” Sam broke off and shook his head. “No, that’s impossible.”

“Unless I’m much mistaken, your brother is in just as much turmoil over his feelings as you are.” Cas looked down at his clasped hands. “I’ve suspected for some time now, but I’ve been unsure how to broach the subject without Dean thinking I’m accusing him. Your brother can be… defensive, particularly when it comes to your wellbeing.”

“No, but-. No, Dean’s in love with you. I’ve seen the way he looks at you. Cas, he’s never looked at anyone the way he looks at you. I can’t ask him for this,” Sam said. “He’s already given up too much for me.”

“He’s not being asked to give up anything. His love for you doesn’t lessen or cheapen his love for me,” Cas said simply.

Confusion furrowed Sam’s brow, and Cas huffed out a breath.

“I’m sure you’re familiar with my--” he hesitated, “ _reputation_. As I understand it, it’s something of a rite of passage for upperclassmen to shock the freshmen with tales of my debauchery. While the one about the lesbians, the tent, and the pancake syrup is false, some of the rumors are grounded in fact. Namely, that I’m familiar with relationships involving more than two people.”

Sam opened his mouth, made a choking sound, and closed it again. This was seriously not a conversation he’d expected to have. Ever.

Cas smirked. “It wasn’t all orgies, you know. Some of them were committed polyamorous relationships. That’s what I’m suggesting. Dean doesn’t love me any less because he loves you, just as my affection for you does not lessen my feelings for him.”

“Your affection for me?” Sam managed, because really, that was the easiest part of that sentence to deal with.

Cas tilted his head. “Forgive me. I assumed you were aware. You were the only student I’ve ever found myself seriously attracted to. You’re bright and resourceful and willing to work for what you want. I find it refreshing. Of course, I never would’ve acted on my attraction while you were my student, but now, well.”

“Now?”

“Now I care for both you and Dean very deeply. A poly relationship seems like the ideal solution, if that’s something the two of you would be comfortable with. I mean, I don’t wish to sound vain, but judging by the way you stared at me during lectures, you’re attracted to me as well.”

Sam licked his lips. “Yeah, I am. But Cas? You know it’s more than that, right? I don’t just--” He ran a hand back through his hair. “You mean a lot to me.”

The words felt flat compared to what he wanted to convey. So many of Cas’ students wanted in his pants. To fuck him or be fucked by him, it didn’t matter. They looked at him like a piece of meat, something to drool over for an hour and fifteen minute lecture. Yes, sex with Cas would be fantastic, but that wasn’t what mattered to Sam.

What mattered most were the afternoon lunches and bad action movies, and he wasn’t willing to trade that for sex. It was the same way he would never trade 80s hair metal and prank wars for sex with Dean. Cas was like family, with all that Sam’s fucked up definition of family apparently implied, and he didn’t want to lose that.

Cas chuckled. “I know, Sam. I wouldn’t be suggesting this if I thought you only considered me a hot piece of ass.”

A startled laugh escaped Sam. “Yeah, well, all of this is assuming Dean agrees. Hell, assuming he won’t freak the fuck out if I tell him that I, you know.”

The older man sobered. “Regardless of whether your brother agrees to a polyamorous relationship, you need to tell him. He won’t blame you for your feelings, Sam, and perhaps it will stop him from blaming himself for his own.”

Sam wanted to argue, wanted to find another reason to keep lying to his brother, but he couldn’t. If there was even a slight chance that Dean felt the same way, Sam knew he had to say something. Dean felt guilty when they ran out of milk for the cereal; Sam hated to think how guilty he would feel over being attracted to his brother.

As if summoned, the back door swung open, and Dean stuck his head out. “Sam? Cas? What’re you guys doing out-- ”

He drew up short at the sight of Sam’s red eyes and Cas’ intent expression. “What’s going on? What’s wrong?”

Worry tightened Dean’s voice, and Sam knew he couldn’t escape the conversation without lying his ass off. He could already feel Cas’ Judging You eyes for even considering it.

Sam took in a long breath through his nose. This felt like a suicide mission. “I need to talk to you, Dean.”

Even under the dim light, Dean visibly paled. “Uh, yeah. Okay.”

Cas got to his feet. “Should I leave the two of you alone?” he asked. His eyes flicked between the brothers, holding Sam’s.

Sam caught his arm. “Stay. Please.”

The words came out more pleading than he intended.

“Very well,” Cas agreed. “Let’s go back inside, then. This conversation is probably better held in private.”

And yeah, Sam realized. They’d totally been sitting outside talking about incest, polyamory, and student/teacher relationships where anyone walking by could overhear. Good thing the neighborhood was pretty quiet after ten pm.

Dean kept his head down as they made their way back inside. Cas took the lead, herding them to the kitchen table. Because really, where better to discuss incest? Dean perched tensely on the edge of a chair, reluctantly meeting Sam’s eye from under his eyelashes.

“So what’s going on?” he asked.

“It’s about what happened earlier,” Sam said.

“I thought you said everything was okay.”

It hurt a little, hearing that tone and knowing Dean fully expected the rug to be pulled out from under the happiness he’d carved out for himself. All of Sam’s brain cell screamed that this was a bad idea, and he hoped beyond words that he wasn’t about to realize any of Dean’s fears.

“It was. Is.” Sam said. “It’s about me, Dean. There’s something you need to know.”

“Okay,” Dean said, drawing out the word.

Sam drew a shaky breath. Under the table Cas squeezed his knee reassuringly. “I wasn’t just watching Cas before.”

Dean raised his eyebrows. “Dude, it’s cool. No one’s gonna’ blame you for being curious.”

“Dean, I wasn’t just watching Cas _,_ ” Sam repeated slowly. “I was watching you.”

Dean opened his mouth, clearly intending to make a joke, but then the meaning of Sam’s words seemed to sink in. His face crumpled.

“Sammy.”

That one word held so much – confusion, pity, warning – that Sam knew his brother understood what he was trying to say.

“I can’t—I can’t help it, and I don’t know what to do. I know this isn’t what you want to hear, but I’m sick of the guilt and the self-loathing and dating girls and hoping it’ll just go away. It’s been nearly eight years. I’m tired of lying through omission and waiting for you to figure it out and think I’m disgusting.”

Sam felt childish and lost saying the words aloud. For the first time since their father died, he wanted his big brother to hug him and tell him everything would be okay, that they’d figure it out. Cas’ world of idealistic polyamory felt like a distant dream. In that moment all Sam wanted was his brother’s acceptance.

Dean stared, slack-jawed.

The lack of response felt like too much in the silence. “Please, Dean. Say something. Anything,” Sam added a little desperately.

“You’re right, it’s not what I want to hear, but I could never—Jesus, Sam, I could never think you’re disgusting.”

The words washed over Sam, leaving a relief he’d never known. Before Sam registered what he was doing, he was out of his chair and hugging his brother. After a startled moment, Dean’s arms came up to his back. With Dean sitting and Sam standing, the angle was awkward, but it didn’t matter.

“Thank you,” Sam whispered.

Dean gripped him tighter. His gaze shifted over Sam’s shoulder to where Cas was silently watching, a small smile twisting his lips. “You knew about this.”

“I suspected,” Cas said. “Seeing how upset Sam was tonight confirmed it.”

“And you’re, what? Okay with this? I mean, don’t get me wrong, I’m glad you’re not freaking the fuck out, but most people would suggest some intense counseling, not a heart to heart in the kitchen.”

“When have I ever been ‘most people?’ Ignoring the greater cultural taboo, there is nothing harmful about Sam’s feelings.” Cas took a breath and drummed his fingers on the table. “Just as there’s nothing wrong with your attraction to Sam.”

Dean stood up abruptly, pulling away from his brother’s embrace like he’d been burned. “What’re you talking about?”

“Dean, feigning ignorance is very unbecoming.”

“I don’t—It’s not li—” Dean took a step towards Cas before backing up several feet. He looked on the verge of fleeing.

“If you say ‘It’s not like that,’ I swear, Dean...” Cas sighed. “Can we please stop pretending you don’t know exactly what I’m talking about?”

“Then why the fuck would you stay with me if you knew?” Dean spat like a cornered cat ready to lash out with claws and teeth. “What, did it ‘ _fascinate’_ you how fucked up I am?”

Cas pulled a face. “That’s not the reason, and you know me better than to truly believe it could be. Please calm down and quit threatening to make a break for the door.”

Dean visibly deflated. This was Castiel, _nice-to-children-and-tourists Castiel_ , the man who caught mice in Tupperware bowls and carried them to the woods rather than set mouse traps. Cas may be many things, but cruel wasn’t one of them.

“Cas, I’m in love with you. You’ve got to believe me,” Dean said pleadingly, pointedly avoiding looking at Sam. “I can’t lose you.”

The implied “don’t leave me” hung as clearly as if it’d been spoken. Sam’s chest ached at how desperately afraid his brother looked in that moment.

Cas’ eyes softened. “Why are the two of you so convinced that love is a finite resource?” he asked gently. “If you loved Sam only as your brother, there’d be no question of your love for me. You don’t love me any less just because your feelings have turned into something more than conventionally brotherly.”

“If you really believe that, then why drag this out in the open, huh?” Dean asked. “I’m sure you’ve got our best interest at heart, or whatever, but shining a light on our fucked up shit won’t make the problem go away.”

“Dean, there is no problem. That’s what I wanted to show you. This is something you can have.”

“So, what? You’d actually excuse incest?” Dean asked, incredulous. He still wasn’t looking at his brother. “As in the act, not the idea?”

“In this case, yes. Both of you are consenting adults who’ve been beating yourselves up over something you can’t help. I’m suggesting that we try a polyamorous relationship.”

“So, what? ‘Threesomes, not love triangles?’ No way Sammy’s onboard with this.”

Sam scowled. “ _Sam_ is standing right here, and yeah, I am. Dean, look at me.”

Reluctantly, Dean lifted his eyes to meet his brother’s.

“What Cas is suggesting isn’t just a threesome. Hell, it doesn’t even have to involve a threesome. Polyamory is about love and the idea that it’s not something you run out of.”

Cas stood, a smirk pulling at one corner of his mouth. “This is a way we can all be happy. And if there’s a threesome involved, well, all the better.”

Even amidst all of the seriousness, Sam wanted to laugh. Clearly Cas hoped for a threesome.

“And you’d be okay with that?” Dean’s voice came out thick with emotion. He looked between the other two men. “Both of you?”

In answer, Cas placed a hand on Sam’s waist and drew him closer. He leaned in and paused, giving Sam a chance to back out. Nerves spiked in Sam’s stomach, but he let the older man close the distance without hesitation. Cas brought a hand up to Sam’s jaw and changed the angle to deepen the kiss. He sucked at Sam’s lower lip, nipping slightly. Sam gasped, and Cas took the chance to wind his tongue around Sam’s.

And damn, Sam had never been kissed like this before, firm and guiding and caring all at once. With the girls he’d dated, he’d always been the one leading, but now it took all of his flagging brain power just to keep up. Cas broke the kiss and nuzzled at the base of Sam’s ear before looking at Dean.

“Come here,” he said. His tone was still gentle despite its seductive edge, like he was afraid of scaring Dean off.

Which, judging by his wide eyes and the stunned part of his lips, was a distinct possibility.

Dean’s feet seemed to carry him forward without his notice. Cas kissed him, hand still resting on Sam’s waist, and Dean responded instinctively. The kiss was familiar, more warmth and reassurance than actual seduction. When they broke apart, Cas pressed their foreheads together and hummed happily. Dean kept his eyes closed, a reluctant smile relaxing the tension from his face.

Sam couldn’t help smiling at the sight. He’d never seen his brother like this, so comfortable trusting of another person. It’d always been just the two of them cocooned in an impenetrable bubble that no one, not even their father, had been able to breach. And yet now Cas was wrapped up with them, able to see all of their secrets and fears, but still willingly standing by them.

Cas moved to stand behind Dean, leaving the space between the brothers empty. Sam met Dean’s gaze. This was the moment to back out. Past this, everything changed.

“It’s okay, Dean.” Cas put his hands on Dean’s hips and kissed his neck softly. “It’s all okay, I promise. Just say stop, and we will.”

Cas’ words seemed to assuage some of Dean’s anxiety, and he nodded, visibly swallowing. Sam moved forward and cupped the base of Dean’s skull, fingers running through the bristly hair. He held his brother’s gaze for a moment longer before closing the distance between them.

At first it was nothing more than the press of damp lips. Then, as they found their equilibrium, they began to move against each other. They were out of sync for an awkward moment, but then Dean tilted his head and Sam pressed forward, and everything fell into place.

The kiss was relatively chaste, but Sam couldn’t help the groan that slipped out of him. He moved closer, pressing them chest to chest. Kissing Dean was wholly new but also familiar in a way that knotted Sam’s stomach. This close, Sam was bombarded with Dean’s scent, something he’d smelled his entire life, but never like this. He remembered smelling that same scent as a child when he’d cried and held on to the front of Dean’s shirt.

So much about this should’ve registered as _wrong wrong wrong_ , but instead, all the he could think was how _right_ this felt, like some missing piece had slotted into place.

“You alright?” Sam asked, pulling back just enough to see his brother.

“Yeah,” Dean answered breathlessly. “Just… Wow.”

Cas chuckled and looped his arms around the taller man’s waist. Dean leaned back into the embrace, knees weak. Sam kissed him again, deeper this time. His free hand came up to thread through Cas’ hair as the older man trailed kisses down Dean’s neck. The embrace was warm and intimate and everything he’d never let himself dream about, and Sam wanted to stay like this forever.

He pressed even closer, forcing Dean to strain to keep the angle of the kiss with their height difference. Without thinking, he let his hips cant forward to meet his brother’s. The press of their clothed erections shocked a gasp out of Dean.

“Sam,” he said, sounding panicky.

Sam backed off a little, kissing along the side of his face. “It’s alright Dean,” he murmured. “We can slow down, if you need.”

“I’m okay,” he said, pressing his face to the crook of Sam’s neck. “Just trying to make myself relax, you know? Kinda’ feels like someone’s going to say ‘April Fools’’ any minute now.”

“Perhaps you’d feel more comfortable in the bedroom,” Cas said. He skimmed his fingers under the hem of Dean’s shirt. “If you want to continue, that is. I don’t wish to rush you into anything.”

“I—Yeah. Bedroom sounds good,” he said. He started to pull away but paused, leaning up to kiss Sam quickly. “Good?”

A goofy grin spread over Sam’s face. “Very good.”

The three made it half-way to the bedroom before Cas pushed Dean against the wall and kissed him fiercely. His knee found its way between Dean’s legs, thigh pressing into the obvious bulge there. He broke the kiss long enough to tug Dean’s shirt over his head before leaning in again. Cas ducked his head to press open mouthed kisses down Dean’s sternum. He detoured to suck one of his pebbled nipples, hand coming up to play with the other.

Sam felt a bit voyeuristic watching them. They were so comfortable with one another that he wondered if he was just going to unbalance the equation.

Dean groaned under Cas’ ministrations and leaned his head back, hooded eyes finding Sam’s. Some of his worries must’ve been written on his face, because Dean gripped Cas’ wrist, drawing his attention.

“Come on. Bedroom, remember? It’s little hard to have a threesome against a wall.”

 “My apologies. It’s been quite a while since I’ve had more than one partner at a time.” Cas smiled ruefully.

Sam stared for a moment before breaking into a grin. That was the same chagrinned smile Cas used to give when he had a correction to make during a test. Which was… kind of hot, actually. Seriously, how many people actually got to have a threesome with the hottest professor on campus?

Cas started towards the bedroom before pausing. He looked at Sam. “Time for the unsexy part,” he said. “Did you get tested at the Student Health Center’s STI screening drive last month?”

“Yeah,” Sam answered, perplexed. “They had all their volunteers do it to set an example.”

“And everything came back good? No sex since then?”

 “Um, no. None. Why?”

“Good. Just needed to know how careful we need to be.” Sam furrowed his brow, and Cas clarified, “Dean and I got tested last month. You didn’t think we were going bare just for the risk of it, did you?” He smirked and, yes, _sauntered_ off towards the bedroom.

“Dean?” Sam glanced at his brother, who was staring pointedly at the ceiling with arms crossed, a blush creeping steadily up his neck. Sam knew he wasn’t shy about sex; he was shy about the fact the he cared about someone enough to get an STI test. Sam couldn’t even bring himself to take the golden opportunity to pick on his brother.

“Can we stop talking about this now? Please?” Dean said, looking pained.

“’Safe sex is fun sex,’” Cas sing-songed from down the hall. Sam laughed as Dean covered his eyes with his palm.

When they finally made it to the bedroom, Sam and Dean stood awkwardly, unsure how to proceed. Standing next to the bed made the situation real in a way nothing else had. This wasn’t a dream or a joke. This was the three of them about to have sex.

Cas didn’t suffer the same reservations, it seemed. He pulled his shirt off and tossed it aside in one smooth motion. Dean raised an eyebrow. “Eager?”

“You have no idea,” Cas said, his voice a low growl. He advanced on Sam and tugged at the hem of his shirt before evidently deciding Sam was too tall. “Off,” he ordered.

As soon as the fabric was over Sam’s head, Cas was on him again, kissing him hot and open-mouthed. The same ferocious attention Sam had seen lavished on Dean was now turned on him. The phrase “climb him like a tree” came to mind. Judging by the way Cas had both arms and one leg wrapped around him, Sam had no doubt he was the tree in this equation.

A hand found its way to the bulge in his jean, cupping him firmly. Cas rubbed him through the denim, and the pressure alone was enough to make Sam gasp out. Slender fingers undid his button and pulled down the zipper in one smooth motion. Cas latched onto his neck and licked to the underside of his jaw, hand slipping into the opening of his boxers. He pulled Sam’s cock free and stroked firmly down the length as he rocked his own clothed erection against the taller man’s thigh.

“Cas,” Sam moaned. He ran his hands down the shorter man’s back and over his ass, gripping to tug him closer. Even still mostly clothed, the warm press of their bodies made him want more, regardless of what “more” was.

Cas turned to look at Dean, eyes heavy and dark. “Sit down and watch,” he said, his voice coming out like glass and gravel. Dean obeyed, and Cas smirked. Sam had just enough time to be worried before Cas was sinking lithely to his knees, skimming Sam’s jeans and boxers down as he went. He looked up from under his lashes, eyes shockingly blue even in the dim light. “Has anyone ever done this for you before?” he asked.

Sam knew his answer wouldn’t matter, that this was Cas’ version of poorly timed curiosity. Most likely he’d guessed that Sam had experience with sex, but not very much of it. “Once,” he managed, wincing at the memory. “There were a lot of teeth involved.”

Dean let out a choking laugh, which Cas chose to ignore.

“Well, at the risk of sounding overconfident, I can assure you that this will be a more pleasurable experience,” Cas said, voice like gravel. He eyed Sam’s cock with interest. “Though I must say, it’s not surprising that anyone had trouble with your… _endowment_.”

Before Sam could do more than turn scarlet, Cas leaned forward and licked up the underside experimentally. Apparently pleased, he sucked Sam into his mouth. He made it half-way down the shaft before bobbing back and going again. The hot, wet of his mouth pulled a low moan from Sam. He gave an abortive thrust, and Cas brought his hands to Sam’s hips, both holding the taller man still and keeping his own balance.

Dean looked on from the edge of the bed, stare heavy and heated. His eyes were fixed on the scene before him, and he licked his lips unconsciously when Sam met his gaze.

Sam wasn’t sure where to put his hands. He wondered if it would come off as pushy if his put his fingers in Cas’ hair. Unable to decide, his hands flutter restlessly at his side. Cas pulled back to catch his breath and guided Sam’s hand to his hair. “It’s okay,” he assured him. “Just leave me enough room to move.”

He circled the head of Sam’s cock with his tongue before sinking down again, determinedly working against his gag reflex. That combined with his fastidious concentration made for easily the hottest thing Sam had ever seen. He threaded his fingers through Cas’ hair, mussing it this way and that, fascinated by how soft it was. He tried not to pull and just let his hand go with the movement of Cas’ head.

Then Cas swallowed against him, and Sam made a very undignified squeaking noise, instinctively tightened his hold.

Cas chuckled low without backing off, and the vibrations sent spikes pleasure through Sam. He reached back blindly for support, knees threatening to give out. Dean stepped up behind him, wrapping an arm around his brother’s waist.

“Lean back,” he said. “I’ve got you.”

Sam did as he was told and let Dean take some of his weight. He turned his head to capture Dean’s mouth in a wet tangle of tongues and teeth. Below, Cas continued his ministrations, sucking hard enough to hollow his cheeks. The noises he was making as he bobbed his head were obscene, almost as much so as he image he cut, fully clothed on his knees, blue eyes hooded and pupils blown.

Sam moaned and let his head loll back onto Dean’s shoulder, forcing his hips to stay still and not thrust to meet every sucking bob for Cas’ head. Dean rubbed his cheek against Sam’s bared neck. Sam knew he’d have some serious stubble burn in the morning, but he couldn’t bring himself to care.

“You two have no clue how amazing you are,” Dean said, rocking steadily against Sam.

The rough drag of denim over his bare ass only heighted Sam’s arousal. All at once it was too much. “Cas,” he warned.

Cas pulled off and looked up, lips glistening and puffy. He ran the back of his hand over his mouth as he stood. Sam reached to finish himself off, but Cas caught his hand and raised it to his mouth to kiss his palm. It was a strangely chaste gesture for a man who’d just been on his knees.

“Not yet.”

Cas leaned forward and licked into Dean’s mouth. The kiss was slow and deep, wringing a desperate moan from Dean, who ground his erection even harder against Sam. Then the realization hit Sam like a punch to the gut: Dean could taste him on Cas. Sam felt winded from the thought alone.

Cas broke the kiss and began shedding his remaining clothes. Lean muscles rippled over his back, and Sam couldn’t look away. Without thinking, he ran a hand down his toned thigh. He knew Cas ran marathons for fun, but it was still hard to believe this was what he was hiding under all those layers.

“Pants,” he ordered Dean, leaning into Sam’s touch. As Dean unbuckled his belt, Sam wondered if it was the excitement of a threesome or if he was always this forceful in bed. Somehow he guessed it was the latter.

Sam couldn’t help staring as Dean stepped out of his pants. He’d seen Dean naked countless times over the years, but this was first time he’d been able to look his fill without the pang of guilt. Dean rubbed the back of his neck then crossed his arms defensively, awkward under the scrutiny.

“Don’t,” Sam said, pulling his arms back down. “S’okay.” He ran his hands down Dean’s sides, feeling the movement of his ribs with each shuttering inhale. He stared in wonder as his finger traced over smooth skin occasionally broken by the fine ridges of scars. He followed the slope of hip muscle to the dark hair at the base of his brother’s erection.

“Sammy,” Dean breathed. In warning or in desperation, Sam couldn’t tell. He leaned forward to kiss him, closing his hand around the shorter man’s length. Dean gasped into his mouth as Sam twisted his wrist. “Sam,” he said again, and this time it was definitely pleading.

Sam led him backwards and pressed him down onto the bed. They landed in a tangle of limbs, yet somehow, his hand never lost its rhythm. “Alright?” he asked as he braced himself over his brother.

Dean’s only response was to tug Sam back down to his lips. His palms ran desperately over every available inch of skin, stroking down Sam’ chest and back up his sides.

The bed dipped as Cas joined them. He trailed a lingering hand over Sam’s back and pressed something into his palm. Glancing down, Sam realized it was a bottle of lube. His nerves ratcheted up again, because he’d never slept with a guy before and most definitely never two guys at the same time. He knew the logistics of it, but knowing something and properly applying it to another person were two very different things.

Cas seemed to sense his unease.

“Too much too soon?” he asked. “We can slow down if it’s too overwhelming.”

Sam shook his head. “I—No. I want to.”

He meant it. “ _Overwhelming_ ” was about right, but he wanted this. God he wanted it, and not just because he was swept up in the moment. Maybe jumping into bed with your brother and former professor and going straight for the penetrative sex was a bit hasty from any sane perspective, but here and now, with Dean and Cas, it felt right. They were already shattering the rules and dancing atop the broken pieces, so why not go all the way?

Besides, if they stopped now, Dean would probably convince himself that this was all a horrible idea.

“Would you like to watch us first?” Cas offered.

Sam let out a breath and nodded. He started to move away, but Dean caught him around the waist and maneuvered him onto his side. Dean lay on his back with Sam pressed full-body against him, cock riding against Dean’s hip. Sam slipped an arm under his neck and watched as Cas took his place on top of him.

Cas flicked open the cap of the lube and squeezed some onto his fingertips, rubbing them together to warm it. Cas looked inquiringly up at Dean, who nodded. Sam watched as he moved his hand to Dean’s entrance, fingers circling teasingly before pressing in.

It surprised Sam how little resistance Dean’s body offered. Over than the tension of arousal thrumming through his him, Dean was almost entirely relaxed, perfectly comfortable with Cas touching him so intimately. He’d assumed that Dean would prefer being the one on top, if for no other reason that he couldn’t imagine his brother trusting anyone with this.

But judging by the ease with which Cas added a second finger, this was something the two of them did often – and if the breathy whining noises and way Dean rocked onto Cas’ hand were anything to go by, it was also something he enjoyed.

Cas scissored his fingers, massaging the ring of muscles before adding a third. His thumb traced delicately over the smooth skin behind Dean’s balls, rubbing just hard enough to elicit a gasp from the man above. On impulse, Sam reached down and rubbed Dean’s hole around Cas’ fingers. Dean let out a ragged moan and thrust his hips down to meet them. Carefully, Sam slipped his finger in next to Cas’, tugging at the rim.

“Oh god,” Dean managed, letting his knees fall open wantonly and arching up into their touch. Sam thrust his finger in time with the movement of his hips. Apparently he did something right, because Dean’s whole body jerked, and he gave a low, keening moan.

Cas leaned forward, arm braced next to the other man’s head and caught his mouth in a long, deep kiss. “Ready?” he asked.

“Fuck, come on. Please, Cas.”

Cas pulled his fingers out and slicked himself with lube. Sam moved aside to give him room, watching transfixed as Cas caught Dean under the knees, holding him open. He sucked biting kisses up the soft skin of Dean’s inner thigh, leaving a trail of red marks in his wake, and lined himself up. He pushed in on one long, slow thrust. Both of them gasped as he bottomed out, and they stilled, taking a moment to find their equilibrium.

After giving Dean time to adjust, Cas gave a couple shallow, experimental thrusts before pulling almost all the way out and pushing back in, slow and deep. Dean’s legs circled his waist, heels locked against his lower back. “Cas. Oh god, _Cas_ ,” Dean panted. He leaned up to capture the other man’s mouth.

Sam watched the messy tangle of their tongues, and suddenly, he felt like an intruder. What the fuck was he even doing here when clearly Dean and Cas were perfectly fine on their own? Jesus, they had more chemistry than most nuclear testing facilities. They were so familiar with each other’s bodies, each other’s hot spots and turn-ons. What did he think he was going to accomplish by walking into this?

Abruptly, his thoughts were broken by a hand squeezing his ass. Dean’s hand, to be precise.

“Sam, you can do more than watch,” Cas growled out, “Fuck, touch us.”

He caught Sam’s hand and guided it down to where he and Dean were joined. Sam could feel everything from the slick in and out movement of Cas’ cock to the way Dean’s hole stretched around him. It was dirty and hot and sent a new wave of arousal coursing through him. Without thinking he ground his own erection against his brother’s hip.

“That’s it,” Dean encouraged with a moan. “Come on, Sam.”

Cas sped up his pace, thrusts coming hard enough to rock the bed. Sweat shined on his neck, and Sam watched appreciatively as the muscles of his shoulders and thighs flexed with each movement.

Sam grasped Dean’s cock where it lay half-hard against his stomach. Dean rolled his head on the pillow, arching up into every caress. Jesus, he’d probably punch Sam for thinking it, but he was beautiful like this, spread out and unselfconsciously given over to pleasure. Sam propped himself over Dean and kissed him, incongruously soft and gentle considering he could feel each of Cas’ thrusts translated through this brother’s body.

“Dean, Dean,” Cas chanted emphatically. “Oh, yes, _Dean_.”

He was starting to lose his rhythm, hips stuttering as his thrusts got rougher, low grunts punctuating each. Dean tightened his legs around him to pull him in deeper. “Come on, Cas,” he said, tilting his head back and arching up. “Come for me. Come on, baby.”

Cas looped an arm under Dean’s waist to bring him closer still. His thrusts tapered off into little more than rough grinding as his eyes fluttered closed. Cas’ body shook with his release, arms trembling. Sam stroked down his brother’s cock to finish him off, but Dean’s hand stilled his movement. Sam watched in confusion as he gripped the base of his erection roughly, staving off his own orgasm.

Cas stilled after a minute, and a contented sigh escaped him. He ran a hand blindly up Dean’s chest and cupped his jaw affectionately. His eyes opened slowly, his face the picture of relaxed afterglow, and the look he gave his lover was nothing short of adoring. Neither of them said the words, but the look passing between them was as good as the most vocal declaration of love.

Sam felt even more voyeuristic seeing this than watching them fuck. He understood how much it meant that they’d invited him to be a part of something so intimate. He felt privileged that they trusted him enough to let him see a side of their relationship that no one else got to. Sam had never seen his brother this bare, and it had nothing to do with his state of undress.

Cas looked at Dean’s still-hard cock and raised his eyebrows in a silent question. Dean’s eyes flicked to Sam, and Cas’ eyebrows climbed higher. “Are you sure?” he asked. “I don’t want to push you into something you’re not comfortable with, yet.”

“Cas, we left what I’m comfortable with behind in the kitchen when I kissed my little brother.”

Worry furrowed the older man’s brow. “Dean, I—”

Dean leaned up and caught his mouth, effectively silencing him. “S’okay,” he said.

Cas smiled and pushed himself upright, his softening cock slipping out. Dean flinched slightly at the sensation. On impulse, Sam reached down and ran his fingers through the mess Cas had left. It should’ve been gross, and maybe it would’ve been if he wasn’t so insanely turned-on, but right then that was the hottest thing Sam had ever done.

“Fuck.” Dean jerked.

Sam hesitated, unsure if that was a good “fuck” or a bad “fuck,” but then Cas smirked. “Amazing, isn’t it? He’s already so in tune with what you like,” he said.

And that made something warm jump in Sam’s gut. This was something Dean found just as hot as he did. Spurred on by that thought, he slipped a finger into his brother, who moaned and rocked against him.

“Shit, come on,” he said, sitting up abruptly.

Cas moved to sit against the headboard, and tugged Sam to follow him. Confused, Sam went where he was guided, sitting so they were pressed back to chest. Cas trailed light kisses over his jaw-line until he found his mouth. At this angle, it was more a wet tangle of tongues than an actual kiss.

Cas’ orgasm had made him mellow, and he wrapped his arms languidly around Sam’s waist. The embrace was warm and perfect, and Sam relaxed back into it automatically, tracing a hand down the older man’s thigh. Bracketed between his legs, Sam could feel Cas’ cock pressing soft and a little sticky against him, but far from being unpleased, it was intimate and oddly comforting.

Pushing himself onto his knees, Dean caught up the lube bottle and squeezed some onto his fingers before reaching behind him. Sam didn’t realize what he intended until he crawled forward to straddle him, knees between the double parentages of Sam and Cas’ legs. He kissed up Sam’s chest, detouring to lick over his collarbone.

“You sure about this?” Dean asked. “There’s no turning back if we do this.”

And, yeah. This was something even they couldn’t ignore, Winchester denial be damned.

 “Dean, I’ve wanted you since I was thirteen. I want _you_ , like this, and I don’t want to wake up in the morning and pretend it never happened.”

Dean leaned forward, arms looping around his brother’s neck, and caught his mouth in a slow, deep kiss. Sam licked warmth and reassurance into his mouth, trying to assure him that everything was alright.

“Just say stop, and I will,” Dean said, pulling back just enough to look Sam in the eye.

“I’m not going to.”

The words felt as much like a warning as a promise. If Dean wanted off this roller coaster, he needed to say so, not count on Sam to do it, because that wasn’t about to happen.

Reaching back, Dean slicked up Sam’s cock and tossed the lube aside. He repositioned himself over his brother’s cock, forearms braced on his shoulders for support, and Sam couldn’t help holding his breath for a long moment.

Eyes staring directly into his, Dean lowered himself down. The drag of bare skin as he sank onto Sam’s cock was exquisite. Sam’s breath huffed out in a long exhale, and he gripped his waist instinctively. Dean was burningly hot around him, tight and slick and perfect.

Behind them, Cas moaned in appreciation. One of his hands came forward to push back the hair sticking damply to Dean’s forehead while the other smoothed up Sam’s chest to play with his nipples.

“Cas,” Sam moaned at the sensation. “Dean.”

After several endless moments of nothing but the slow slide Dean’s heat engulfing him, Dean sat flush against Sam. His breath came in stuttering pulls, and his chest heaved where it was pressed to Sam’s.

Dean undulated his hips without pulling back, adjusting to the slide-pull of Sam’s cock sheathed within him, longer than Cas’ had been. He rocked insistently, building up a steady rhythm before pushing himself up and back down slowly. He repeated the motion again and again, gaining momentum with each undulation.

Pleasure shot through Sam, and he gave an abortive thrust upwards.

“Come on,” Dean gasped out, speeding up his pace. “You’re not going to break me. Come on, Sammy.”

And that – Dean calling him ‘Sammy’ in that sex-rough voice – snapped whatever self-restraint Sam had had. It was a reminder of what they were to one another, a reminder that they were breaking one of society’s greatest taboos, all while Cas watched and encouraged them.

Sam gripped his brother’s hips, pulling him down to meet his thrust up.

“Oh god, that’s it.” Dean’s head tilted back in pleasure. “Just like that.”

Sam did as he was told, angling each of his thrusts just so. He watched the play of muscle as Dean moved, each movement up making the muscles of his thighs flex.

Cas kissed and nipped along Sam’s shoulder, sucking what were sure to be bright hickies as he went. His hand moved to cover Sam’s on Dean’s hip, fingers meshing together, and he pulled Dean down onto Sam’s cock even harder. “It’s okay, Sam. He can take it. He likes it rough.”

And there again was the reminder that this was something Cas had done, that this was somewhere Cas had been – under Dean, feeling each rock of his hips.

“Fuck, _yes,_ ” Dean hissed out. “Sammy.”

Sam loved how vocal his brother was. Whenever he’d imaged this – and god help him, he’d imagined it – he’d always pictured Dean as holding something back.

But not now.

Dean was giving him everything he’d never thought he’d be allowed to have, bodies pressed close with no room between them, sweat slicking their way. Dean’s knees gripped his hips tight enough to bruise, and his fingernails were crescent indentations on his shoulders as he pulled himself up and down.

“Dean,” Sam moaned out.

Dean buried his face at the juncture of Sam’s neck, panting breaths coming hot over his collarbone.

“Look at me,” Sam said. He wanted to see him, see his brother as he lost it.

Dean obeyed, turning up pleasure-glazed eyes. The green of his irises were almost completely obscured by his lust-blown pupils.

He pressed their foreheads together, still moving on Sam’s cock, and kissed him desperately without closing his eyes.

Dean started to lose his rhythm, already close from being fucked by Cas. And, okay, that was a really hot thought. All Sam could do was hold on for the ride. Dean’s thigh muscles were starting to tremble, and Sam looped an arm around his waist for support, pulling him closer. His other hand gripped Dean’s cock and jacked him in counter time to his movements.

A low litany of “Sam, Sam, _Sam_ ” echoed through the room on each thrust.

“Jesus, you two are gorgeous,” Cas growled. His breath ghosted hot and damp over Sam’s ear, making the younger man shiver. He tugged at Sam’s earlobe with his teeth and tightened his hold around Sam’s waist. “Look at you two, so lost in each other.”

Cas reached down, fingers meeting Sam’s on Dean’s cock. Dean grunted at the added sensation.

“Cas,” he gasped on a breathless exhale. His arms tightened around Sam’s back.

“We’ve got you, Dean,” Cas growled. “Let go.”

And that was all it took to push Dean over the edge. He came hot and sticky over their hands, moaning out both of their names.

Sam wrapped his arms around Dean, holding his brother close as he shook through his orgasm. Dean pressed his face into Sam’s shoulder, arms around his neck.

Dean’s body contracting around him was enough to make Sam lose it. He pulled Dean flush against him from hip to neck and came buried in him, engulfed in his brother’s warmth. It should have felt wrong, but all Sam could think was how perfect it felt, like a missing puzzle piece slotting into place.

They stayed like that for a long time, the three of them wrung out and clinging to each other. Dean’s scent filled his nose, painfully familiar, and Cas’ hair tickled his neck in a way he could get used to.

It was Cas who broke the silence. “Jesus, if I was ten years younger, I would be ready for round two after watching that.”

Dean’s laugh came out muffled against Sam’s collarbone. Gingerly, he pushed himself up, letting Sam’s cock slip free. His legs were still shaking slightly, and he nearly overbalanced as he tried to move off Sam. Sam shot out an arm to steady him and carefully guided him to the pillows.

Sam and Cas arranged themselves to lie on either side of him. Dean’s head ended up pillowed on Cas’ chest, Cas’ arm looped around his shoulder and fingers playing with Sam’s hair. Their legs were so thoroughly tangled that Sam honestly couldn't say which were his.

“Sammy—” Dean managed. He seemed like he wanted to say more but stopped.

Sam leaned over him and tilted his head up, making him meet his eyes, and yes, that was the look of Dean almost freaking out. “It’s okay, Dean,” Sam said. He knew that was what Dean needed to hear right now. “We've got you, Dean,” he said, repeating Cas’ earlier words.

Sam kissed him softly, wanting to show him that it was all okay – that they were okay. “I love you,” Sam said. He traced his nose over Dean’s jaw. “Always.”

Another shiver ran through Dean at that. He looked at his brother, visibly pushing down the edges of his panic. “Love you, too.” He looked up, caching Cas’ eye and smirking. “ _I love you, too_ ,” he drawled. Despite the smirk and light tone, Sam knew that he meant it.

“You didn’t have to say it for me to know.” Cas leaned forward and caught Dean’s mouth, kissing the smirk off his lips. “But I appreciate it, all the same. You know I love you.”

“Yeah,” Dean said, and if Sam didn't think he’d get punched for so much as thinking it, he’d call that expression sappy.

There was silence for several more moments. The only sound in the room was the rhythmic clicking of the ceiling fan and the faint caesuras of their breathing as it leveled back out. Cas rubbed soothing circles into Dean’s back while his fingers carded gently through Sam’s hair, occasionally twisting the individual strands around his index finger.

“Is it bad that I really want a cigarette?” Cas asked to the room at large.

A beat of silence followed his words before Sam and Dean started laughing. After a moment, Cas joined them.

“Take it as a compliment. I haven’t smoked since grad school.”

Maybe sometimes, Sam realized, you do choose your family. Because this, right here? This was his. This was _theirs_.


End file.
